Numerical-simulation of heat transfer characteristics for laminar flow over a two dimensional backward-facing step
1.School of Energy and Power Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 2.School of Mechanical Engineering, Nantong University, Nantong, Jiangsu 226019, China
Abstract：A two-dimensional incompressible numerical model of the backward-facing step flow was established. The influences of Reynolds number, step height(S) and channel height(H) on the Nusselt number at the bottom wall surface downstream of the step were discussed in the laminar flow range of Re from 100 to 400. The results show that for constant expansion ratio of ER, the positions of inflection points for Nusselt number curves are stable when an additional recirculation region appears on the upper wall. Increasing the Reynolds number can improve the upstream Nusselt number of inflection points, but has slight effect on the downstream Nusselt number. When S is constant with decreased H, ER increases from 1.33 to 3.00, and the variation range of Nusselt number(Nu) increases with the position of Nu peak moving upstream. When H is constant with increased S, the variation range of Nusselt number(Nu H) can be divided into two parts. With the increasing of ER from 1.33 to 2.00, the value of NuH peak essentially remains unchanged, while the position of NuH peak moves downstream. With the increasing of ER from 2.00 to 3.00, the value of NuH peak rapidly increases, while the position of NuH peak changes slightly.
2014, Vol. 35 
